All substance use has a function and a meaning for a young person. In many instances, by the time a young person has developed some problems around their substance use, the function of their use that was present at the beginning of their using has changed.  It is important to recognise and understand this change over time.    

D1. ‘Functional analysis’ of substance using behaviour
A functional analysis of a young person’s substance use is a form of behavioural assessment.  It provides the practitioner, the young person and others involved in their care with well-structured information that can be used to formulate well matched and targeted goals and strategies.  Functional analysis involves understanding three main components:

  1. the role of substance use in the young person’s life,
  2. factors that contribute to maintaining the substance use, and
  3. obstacles that may impede the effectiveness of strategies put in place

G2ii.Chain Analysis
An alternative form of behavioural analysis used in Dialectical Behaviour Therapy (DBT) is a chain analysis. Like a functional analysis, a chain analysis involves defining a problem and gathering evidence to determine what is causing it, what is preventing its resolution, and what tools might be available for solving it. Chain analysis can help the practitioner and client gain a perspective on several factors that may be working in specific contexts to maintain problem behaviours, or prevent the use of skill-based strategies. 

Substance use diary
Another strategy that young people can use to learn more about their substance use is keeping a “substance use diary”. The diary can be kept over a specified time, usually a week, to record details of their substance using behaviour including time and place, whether it was with anyone else, how much of what was used, how much was spent, how they were feeling at the time they were using etc.

An example of a substance use diary can be found in the World Health Organisation publication: Self-help strategies for cutting down or stopping substance use: a guide.